The invention relates to an automatic vending machine for cooling or heating and vending articles such as canned beverages.
A conventional vending machine is composed of a storage case for storing articles to be sold provided in a housing formed of a thermally insulated box. The storage case is divided into a plurality of compartments. The compartments for storing cold articles at a temperature such as about 5xc2x0 C. are each cooled according to a known cooling cycle and the compartments for storing hot articles at a temperature, for example, about 60xc2x0 C. are heated by electric heaters.
Heretofore, an electric heater is used as a heating means. A great amount of heat is required to obtain the amount of heat enough for the heating. The heat in the heated compartments provided with electric heaters leaks to the compartments for cooling because these cooling compartments and heating compartments are present together. Thus, a greater amount of heat has to be expelled to the outside to the extent of such leak and, therefore, the cooling cycle has to be operated at higher rate, causing a problem of increased running costs.
This invention has made to solve such a technical problem in the prior art.
It is an object of the invention to provide an automatic vending machine accomplishing decrease of the running costs by utilizing effectively the exhausted heat produced by cooling.
According to invention, an automatic vending machine provided with a storage case for articles to be sold provided in a housing formed of a heat-insulating box, the storage case is divided into a plurality of compartments in which the articles contained therein are cooled or heated to be sold through one or more outlets, comprises:
a primary heat unit provided with a compressor and a primary heat exchanger connected with a refrigerant-ejecting pipe and a refrigerant return pipe through a selective valve;
a refrigerant flow-controlling valve for controlling amount of refrigerant flowing into the primary heat unit;
a control apparatus for controlling the refrigerant flow-controlling valve;
a plurality of secondary heat units each having a secondary heat exchanger and being located in each of the compartments; and
a plurality of conduit pipes connecting the primary heat unit with the plurality of secondary heat units, each comprising a high-pressure gas pipe connected with the refrigerant ejecting pipe, a low-pressure gas pipe connected with the refrigerant return pipe, and a liquid pipe connected with the primary heat exchanger:
each of the secondary heat exchangers being connected selectively with the high-pressure gas pipe and the low-pressure gas pipe through a selecting valve;
the liquid pipe being provided with a heating/cooling apparatus connected with a refrigerant flow-controlling valve.
The automatic vending machine according to the invention, so constituted as to have a simply constructed circuit using a uni-functional primary heat exchange unit, can be operated to cool or heat all the compartments simultaneously by a plurality of secondary heat exchangers as well as to cool and heat the compartments selectively by selected secondary heat exchangers at the same time.
Efficient operation by heat recycling is allowed in the case of cooling and heating operation in parallel because the secondary heat exchangers serving then as condensers are connected in series with the primary heat exchanger serving then as an evaporator, thereby facilitating a remarkable decrease in the running costs.
An automatic vending machine according to the second feature of the invention further comprises:
a specified secondary heat unit provided in the cooled or heated compartment, having a secondary heat exchanger connected between a liquid pipe and a low-pressure gas pipe or a high-pressure gas pipe;
the secondary heat exchanger in the specified secondary heat unit having a volume equal to sum of volumes of the secondary heat exchangers in other secondary heat units.
In the automatic vending machine, according to the second feature of the invention, in which the secondary heat exchanger in the specified secondary heat unit is used for cooling, serving as an evaporator, and the secondary heat exchangers in the other secondary heat units are used for heating, serving as condensers, for example, heating by exhausted heat and cooling by heat absorption by these secondary heat exchangers can be balanced without using the primary heat exchanger. Thus, more efficient operation is accomplished because of more effective recovery of heat.